An imaging method is provided. In an example, the imaging method includes a first X-ray image including a ROI of a subject is taken by an image capturing device, a position of the ROI in the first X-ray image is determined, a moving distance and a moving direction for a positioning system is determined based on the position of the ROI in the first X-ray image, and the positioning system is capable of being moved to adjust a positional relationship between the image capturing device and the subject, the positioning system is moved based on the moving distance and the moving direction, and a second X-ray image including the ROI is taken by the image capturing device, and the ROI is located in a center position of the second X-ray image.